upgrade to rails 5.0.0.beta3

- ran `rails rails:update`
- also updated rspec-rails to 3.5.0.beta3 for rails 5 compatibility
- modified puma config

Author: audionerd

Gemfile

@@ -3,7 +3,7 @@ ruby "2.3.0"
 
 #
 # Bundle edge Rails instead: gem "rails", github: "rails/rails"
-gem "rails", "~>4.2"
+gem "rails", "5.0.0.beta3"
 
 # Note: We're using sqllite3 for development and testing
 gem "sqlite3", group: [:development, :test]
@@ -102,7 +102,7 @@ group :test  do
   gem "generator_spec"
   gem "launchy"
   gem "poltergeist"
-  gem "rspec-rails"
+  gem "rspec-rails", "3.5.0.beta3"
   gem "rspec-retry"
   gem "selenium-webdriver", require: !["poltergeist", "poltergeist_errors_ok", "webkit"].include?(ENV["DRIVER"])
 end

Gemfile.lock

@@ -1,45 +1,47 @@
 GEM
   remote: https://rubygems.org/
   specs:
-    actionmailer (4.2.6)
-      actionpack (= 4.2.6)
-      actionview (= 4.2.6)
-      activejob (= 4.2.6)
+    actioncable (5.0.0.beta3)
+      actionpack (= 5.0.0.beta3)
+      nio4r (~> 1.2)
+      websocket-driver (~> 0.6.1)
+    actionmailer (5.0.0.beta3)
+      actionpack (= 5.0.0.beta3)
+      actionview (= 5.0.0.beta3)
+      activejob (= 5.0.0.beta3)
       mail (~> 2.5, >= 2.5.4)
       rails-dom-testing (~> 1.0, >= 1.0.5)
-    actionpack (4.2.6)
-      actionview (= 4.2.6)
-      activesupport (= 4.2.6)
-      rack (~> 1.6)
-      rack-test (~> 0.6.2)
+    actionpack (5.0.0.beta3)
+      actionview (= 5.0.0.beta3)
+      activesupport (= 5.0.0.beta3)
+      rack (~> 2.x)
+      rack-test (~> 0.6.3)
       rails-dom-testing (~> 1.0, >= 1.0.5)
       rails-html-sanitizer (~> 1.0, >= 1.0.2)
-    actionview (4.2.6)
-      activesupport (= 4.2.6)
+    actionview (5.0.0.beta3)
+      activesupport (= 5.0.0.beta3)
       builder (~> 3.1)
       erubis (~> 2.7.0)
       rails-dom-testing (~> 1.0, >= 1.0.5)
       rails-html-sanitizer (~> 1.0, >= 1.0.2)
-    activejob (4.2.6)
-      activesupport (= 4.2.6)
-      globalid (>= 0.3.0)
-    activemodel (4.2.6)
-      activesupport (= 4.2.6)
-      builder (~> 3.1)
-    activerecord (4.2.6)
-      activemodel (= 4.2.6)
-      activesupport (= 4.2.6)
-      arel (~> 6.0)
-    activesupport (4.2.6)
+    activejob (5.0.0.beta3)
+      activesupport (= 5.0.0.beta3)
+      globalid (>= 0.3.6)
+    activemodel (5.0.0.beta3)
+      activesupport (= 5.0.0.beta3)
+    activerecord (5.0.0.beta3)
+      activemodel (= 5.0.0.beta3)
+      activesupport (= 5.0.0.beta3)
+      arel (~> 7.0)
+    activesupport (5.0.0.beta3)
+      concurrent-ruby (~> 1.0)
       i18n (~> 0.7)
-      json (~> 1.7, >= 1.7.7)
       minitest (~> 5.1)
-      thread_safe (~> 0.3, >= 0.3.4)
       tzinfo (~> 1.1)
     addressable (2.4.0)
     archive-zip (0.7.0)
       io-like (~> 0.3.0)
-    arel (6.0.3)
+    arel (7.0.0)
     ast (2.2.0)
     autoprefixer-rails (6.3.6)
       execjs
@@ -60,8 +62,8 @@ GEM
     bundler-audit (0.5.0)
       bundler (~> 1.2)
       thor (~> 0.18)
-    byebug (8.2.2)
-    capybara (2.6.2)
+    byebug (8.2.3)
+    capybara (2.7.0)
       addressable
       mime-types (>= 1.16)
       nokogiri (>= 1.3.3)
@@ -71,8 +73,8 @@ GEM
     capybara-screenshot (1.0.12)
       capybara (>= 1.0, < 3)
       launchy
-    capybara-webkit (1.9.0)
-      capybara (>= 2.3.0, < 2.7.0)
+    capybara-webkit (1.10.0)
+      capybara (>= 2.3.0, < 2.8.0)
       json
     childprocess (0.5.9)
       ffi (~> 1.0, >= 1.0.11)
@@ -139,6 +141,7 @@ GEM
     mini_portile2 (2.0.0)
     minitest (5.8.4)
     multi_json (1.11.2)
+    nio4r (1.2.1)
     nokogiri (1.6.7.2)
       mini_portile2 (~> 2.0.0.rc2)
     parser (2.3.0.7)
@@ -168,21 +171,23 @@ GEM
     pry-stack_explorer (0.4.9.2)
       binding_of_caller (>= 0.7)
       pry (>= 0.9.11)
-    puma (3.3.0)
-    rack (1.6.4)
+    puma (3.4.0)
+    rack (2.0.0.alpha)
+      json
     rack-test (0.6.3)
       rack (>= 1.0)
-    rails (4.2.6)
-      actionmailer (= 4.2.6)
-      actionpack (= 4.2.6)
-      actionview (= 4.2.6)
-      activejob (= 4.2.6)
-      activemodel (= 4.2.6)
-      activerecord (= 4.2.6)
-      activesupport (= 4.2.6)
+    rails (5.0.0.beta3)
+      actioncable (= 5.0.0.beta3)
+      actionmailer (= 5.0.0.beta3)
+      actionpack (= 5.0.0.beta3)
+      actionview (= 5.0.0.beta3)
+      activejob (= 5.0.0.beta3)
+      activemodel (= 5.0.0.beta3)
+      activerecord (= 5.0.0.beta3)
+      activesupport (= 5.0.0.beta3)
       bundler (>= 1.3.0, < 2.0)
-      railties (= 4.2.6)
-      sprockets-rails
+      railties (= 5.0.0.beta3)
+      sprockets-rails (>= 2.0.0)
     rails-deprecated_sanitizer (1.0.3)
       activesupport (>= 4.2.0.alpha)
     rails-dom-testing (1.0.7)
@@ -196,9 +201,10 @@ GEM
       rails_stdout_logging
     rails_serve_static_assets (0.0.5)
     rails_stdout_logging (0.0.5)
-    railties (4.2.6)
-      actionpack (= 4.2.6)
-      activesupport (= 4.2.6)
+    railties (5.0.0.beta3)
+      actionpack (= 5.0.0.beta3)
+      activesupport (= 5.0.0.beta3)
+      method_source
       rake (>= 0.8.7)
       thor (>= 0.18.1, < 2.0)
     rainbow (2.1.0)
@@ -212,25 +218,25 @@ GEM
       rails (>= 3.2)
       rainbow (~> 2.1)
     ref (2.0.0)
-    rspec-core (3.4.4)
-      rspec-support (~> 3.4.0)
-    rspec-expectations (3.4.0)
+    rspec-core (3.5.0.beta3)
+      rspec-support (= 3.5.0.beta3)
+    rspec-expectations (3.5.0.beta3)
       diff-lcs (>= 1.2.0, < 2.0)
-      rspec-support (~> 3.4.0)
-    rspec-mocks (3.4.1)
+      rspec-support (= 3.5.0.beta3)
+    rspec-mocks (3.5.0.beta3)
       diff-lcs (>= 1.2.0, < 2.0)
-      rspec-support (~> 3.4.0)
-    rspec-rails (3.4.2)
-      actionpack (>= 3.0, < 4.3)
-      activesupport (>= 3.0, < 4.3)
-      railties (>= 3.0, < 4.3)
-      rspec-core (~> 3.4.0)
-      rspec-expectations (~> 3.4.0)
-      rspec-mocks (~> 3.4.0)
-      rspec-support (~> 3.4.0)
+      rspec-support (= 3.5.0.beta3)
+    rspec-rails (3.5.0.beta3)
+      actionpack (>= 3.0)
+      activesupport (>= 3.0)
+      railties (>= 3.0)
+      rspec-core (= 3.5.0.beta3)
+      rspec-expectations (= 3.5.0.beta3)
+      rspec-mocks (= 3.5.0.beta3)
+      rspec-support (= 3.5.0.beta3)
     rspec-retry (0.4.5)
       rspec-core
-    rspec-support (3.4.1)
+    rspec-support (3.5.0.beta3)
     rubocop (0.39.0)
       parser (>= 2.3.0.7, < 3.0)
       powerpack (~> 0.1)
@@ -343,12 +349,12 @@ DEPENDENCIES
   pry-rescue
   pry-stack_explorer
   puma
-  rails (~> 4.2)
+  rails (= 5.0.0.beta3)
   rails-html-sanitizer
   rails_12factor
   rainbow
   react_on_rails (~> 5.1.1)
-  rspec-rails
+  rspec-rails (= 3.5.0.beta3)
   rspec-retry
   rubocop
   ruby-lint

bin/rails

@@ -1,9 +1,4 @@
 #!/usr/bin/env ruby
-begin
-  load File.expand_path('../spring', __FILE__)
-rescue LoadError => e
-  raise unless e.message.include?('spring')
-end
 APP_PATH = File.expand_path('../../config/application', __FILE__)
 require_relative '../config/boot'
 require 'rails/commands'

bin/rake

@@ -1,9 +1,4 @@
 #!/usr/bin/env ruby
-begin
-  load File.expand_path('../spring', __FILE__)
-rescue LoadError => e
-  raise unless e.message.include?('spring')
-end
 require_relative '../config/boot'
 require 'rake'
 Rake.application.run

bin/setup

@@ -1,29 +1,34 @@
 #!/usr/bin/env ruby
 require 'pathname'
+require 'fileutils'
+include FileUtils
 
 # path to your application root.
-APP_ROOT = Pathname.new File.expand_path('../../',  __FILE__)
+APP_ROOT = Pathname.new File.expand_path('../../', __FILE__)
 
-Dir.chdir APP_ROOT do
+def system!(*args)
+  system(*args) || abort("\n== Command #{args} failed ==")
+end
+
+chdir APP_ROOT do
   # This script is a starting point to setup your application.
-  # Add necessary setup steps to this file:
+  # Add necessary setup steps to this file.
 
-  puts "== Installing dependencies =="
-  system "gem install bundler --conservative"
-  system "bundle check || bundle install"
+  puts '== Installing dependencies =='
+  system! 'gem install bundler --conservative'
+  system('bundle check') or system!('bundle install')
 
   # puts "\n== Copying sample files =="
-  # unless File.exist?("config/database.yml")
-  #   system "cp config/database.yml.sample config/database.yml"
+  # unless File.exist?('config/database.yml')
+  #   cp 'config/database.yml.sample', 'config/database.yml'
   # end
 
   puts "\n== Preparing database =="
-  system "bin/rake db:setup"
+  system! 'bin/rails db:setup'
 
   puts "\n== Removing old logs and tempfiles =="
-  system "rm -f log/*"
-  system "rm -rf tmp/cache"
+  system! 'bin/rails log:clear tmp:clear'
 
   puts "\n== Restarting application server =="
-  system "touch tmp/restart.txt"
+  system! 'bin/rails restart'
 end

bin/update

@@ -0,0 +1,29 @@
+#!/usr/bin/env ruby
+require 'pathname'
+require 'fileutils'
+include FileUtils
+
+# path to your application root.
+APP_ROOT = Pathname.new File.expand_path('../../', __FILE__)
+
+def system!(*args)
+  system(*args) || abort("\n== Command #{args} failed ==")
+end
+
+chdir APP_ROOT do
+  # This script is a way to update your development environment automatically.
+  # Add necessary update steps to this file.
+
+  puts '== Installing dependencies =='
+  system! 'gem install bundler --conservative'
+  system 'bundle check' or system! 'bundle install'
+
+  puts "\n== Updating database =="
+  system! 'bin/rails db:migrate'
+
+  puts "\n== Removing old logs and tempfiles =="
+  system! 'bin/rails log:clear tmp:clear'
+
+  puts "\n== Restarting application server =="
+  system! 'bin/rails restart'
+end

config/application.rb

@@ -1,6 +1,6 @@
-require File.expand_path("../boot", __FILE__)
+require File.expand_path('../boot', __FILE__)
 
-require "rails/all"
+require 'rails/all'
 
 # Require the gems listed in Gemfile, including any gems
 # you've limited to :test, :development, or :production.
@@ -11,16 +11,5 @@ class Application < Rails::Application
     # Settings in config/environments/* take precedence over those specified here.
     # Application configuration should go into files in config/initializers
     # -- all .rb files in that directory are automatically loaded.
-
-    # Set Time.zone default to the specified zone and make Active Record auto-convert to this zone.
-    # Run "rake -D time" for a list of tasks for finding time zone names. Default is UTC.
-    # config.time_zone = "Central Time (US & Canada)"
-
-    # The default locale is :en and all translations from config/locales/*.rb,yml are auto loaded.
-    # config.i18n.load_path += Dir[Rails.root.join("my", "locales", "*.{rb,yml}").to_s]
-    # config.i18n.default_locale = :de
-
-    # For not swallow errors in after_commit/after_rollback callbacks.
-    config.active_record.raise_in_transactional_callbacks = true
   end
 end

config/boot.rb

@@ -1,3 +1,3 @@
-ENV["BUNDLE_GEMFILE"] ||= File.expand_path("../../Gemfile", __FILE__)
+ENV['BUNDLE_GEMFILE'] ||= File.expand_path('../../Gemfile', __FILE__)
 
-require "bundler/setup" # Set up gems listed in the Gemfile.
+require 'bundler/setup' # Set up gems listed in the Gemfile.

config/cable.yml

@@ -0,0 +1,10 @@
+# Action Cable uses Redis by default to administer connections, channels, and sending/receiving messages over the WebSocket.
+production:
+  adapter: redis
+  url: redis://localhost:6379/1
+
+development:
+  adapter: async
+
+test:
+  adapter: async

config/environment.rb

@@ -1,5 +1,5 @@
 # Load the Rails application.
-require File.expand_path("../application", __FILE__)
+require File.expand_path('../application', __FILE__)
 
 # Initialize the Rails application.
 Rails.application.initialize!

config/environments/development.rb

@@ -9,9 +9,26 @@
   # Do not eager load code on boot.
   config.eager_load = false
 
-  # Show full error reports and disable caching.
+  # Show full error reports.
   config.consider_all_requests_local = true
-  config.action_controller.perform_caching = false
+
+  # Enable/disable caching. By default caching is disabled.
+  if Rails.root.join('tmp/caching-dev.txt').exist?
+    config.action_controller.perform_caching = true
+
+    config.action_mailer.perform_caching = false
+
+    config.cache_store = :memory_store
+    config.public_file_server.headers = {
+      'Cache-Control' => 'public, max-age=172800'
+    }
+  else
+    config.action_controller.perform_caching = false
+
+    config.action_mailer.perform_caching = false
+
+    config.cache_store = :null_store
+  end
 
   # Don't care if the mailer can't send.
   config.action_mailer.raise_delivery_errors = false
@@ -38,4 +55,8 @@
 
   # Raises error for missing translations
   # config.action_view.raise_on_missing_translations = true
+
+  # Use an evented file watcher to asynchronously detect changes in source code,
+  # routes, locales, etc. This feature depends on the listen gem.
+  config.file_watcher = ActiveSupport::EventedFileUpdateChecker
 end

config/environments/production.rb

@@ -11,16 +11,12 @@
   config.eager_load = true
 
   # Full error reports are disabled and caching is turned on.
-  config.consider_all_requests_local = false
+  config.consider_all_requests_local       = false
   config.action_controller.perform_caching = true
 
-  # Enable Rack::Cache to put a simple HTTP cache in front of your application
-  # Add `rack-cache` to your Gemfile before enabling this.
-  # For large-scale production use, consider using a caching reverse proxy like NGINX, varnish or squid.
-  # config.action_dispatch.rack_cache = true
-
-  # Disable Rails's static asset server (Apache or NGINX will already do this).
-  config.serve_static_files = false
+  # Disable serving static files from the `/public` folder by default since
+  # Apache or NGINX already handles this.
+  config.public_file_server.enabled = ENV['RAILS_SERVE_STATIC_FILES'].present?
 
   # Compress JavaScripts and CSS.
   config.assets.js_compressor = :uglifier
@@ -35,27 +31,42 @@
 
   # `config.assets.precompile` and `config.assets.version` have moved to config/initializers/assets.rb
 
+  # Enable serving of images, stylesheets, and JavaScripts from an asset server.
+  # config.action_controller.asset_host = 'http://assets.example.com'
+
   # Specifies the header that your server uses for sending files.
-  # config.action_dispatch.x_sendfile_header = "X-Sendfile" # for Apache
-  # config.action_dispatch.x_sendfile_header = "X-Accel-Redirect" # for NGINX
+  # config.action_dispatch.x_sendfile_header = 'X-Sendfile' # for Apache
+  # config.action_dispatch.x_sendfile_header = 'X-Accel-Redirect' # for NGINX
+
+  # Action Cable endpoint configuration
+  # config.action_cable.url = 'wss://example.com/cable'
+  # config.action_cable.allowed_request_origins = [ 'http://example.com', /http:\/\/example.*/ ]
 
   # Force all access to the app over SSL, use Strict-Transport-Security, and use secure cookies.
   # config.force_ssl = true
 
-  # Set to :info to decrease the log volume.
+  # Use the lowest log level to ensure availability of diagnostic information
+  # when problems arise.
   config.log_level = :debug
 
   # Prepend all log lines with the following tags.
-  # config.log_tags = [ :subdomain, :uuid ]
+  config.log_tags = [ :request_id ]
 
   # Use a different logger for distributed setups.
-  # config.logger = ActiveSupport::TaggedLogging.new(SyslogLogger.new)
+  # require 'syslog/logger'
+  # config.logger = ActiveSupport::TaggedLogging.new(Syslog::Logger.new 'app-name')
+
+  if ENV["RAILS_LOG_TO_STDOUT"].present?
+    config.logger = ActiveSupport::TaggedLogging.new(Logger.new(STDOUT))
+  end
 
   # Use a different cache store in production.
   # config.cache_store = :mem_cache_store
 
-  # Enable serving of images, stylesheets, and JavaScripts from an asset server.
-  # config.action_controller.asset_host = "http://assets.example.com"
+  # Use a real queuing backend for Active Job (and separate queues per environment)
+  # config.active_job.queue_adapter     = :resque
+  # config.active_job.queue_name_prefix = "rails_react_tutorial_#{Rails.env}"
+  config.action_mailer.perform_caching = false
 
   # Ignore bad email addresses and do not raise email delivery errors.
   # Set this to true and configure the email server for immediate delivery to raise delivery errors.

config/environments/test.rb

@@ -12,9 +12,11 @@
   # preloads Rails for running tests, you may have to set it to true.
   config.eager_load = false
 
-  # Configure static asset server for tests with Cache-Control for performance.
-  config.serve_static_files = true
-  config.static_cache_control = "public, max-age=3600"
+  # Configure public file server for tests with Cache-Control for performance.
+  config.public_file_server.enabled = true
+  config.public_file_server.headers = {
+    'Cache-Control' => 'public, max-age=3600'
+  }
 
   # Show full error reports and disable caching.
   config.consider_all_requests_local       = true
@@ -25,6 +27,7 @@
 
   # Disable request forgery protection in test environment.
   config.action_controller.allow_forgery_protection = false
+  config.action_mailer.perform_caching = false
 
   # Tell Action Mailer not to deliver emails to the real world.
   # The :test delivery method accumulates sent emails in the

config/initializers/application_controller_renderer.rb

@@ -0,0 +1,6 @@
+# Be sure to restart your server when you modify this file.
+
+# ApplicationController.renderer.defaults.merge!(
+#   http_host: 'example.org',
+#   https: false
+# )

config/initializers/assets.rb

@@ -1,7 +1,7 @@
 # Be sure to restart your server when you modify this file.
 
 # Version of your assets, change this if you want to expire all your assets.
-Rails.application.config.assets.version = "1.0"
+Rails.application.config.assets.version = '1.0'
 
 # Add folder with webpack generated assets to assets.paths
 Rails.application.config.assets.paths << Rails.root.join("app", "assets", "webpack")

config/initializers/cookies_serializer.rb

@@ -1,3 +1,5 @@
 # Be sure to restart your server when you modify this file.
 
+# Specify a serializer for the signed and encrypted cookie jars.
+# Valid options are :json, :marshal, and :hybrid.
 Rails.application.config.action_dispatch.cookies_serializer = :json

config/initializers/cors.rb

@@ -0,0 +1,16 @@
+# Be sure to restart your server when you modify this file.
+
+# Avoid CORS issues when API is called from the frontend app.
+# Handle Cross-Origin Resource Sharing (CORS) in order to accept cross-origin AJAX requests.
+
+# Read more: https://github.com/cyu/rack-cors
+
+# Rails.application.config.middleware.insert_before 0, Rack::Cors do
+#   allow do
+#     origins 'example.com'
+#
+#     resource '*',
+#       headers: :any,
+#       methods: [:get, :post, :put, :patch, :delete, :options, :head]
+#   end
+# end

config/initializers/inflections.rb

@@ -4,13 +4,13 @@
 # are locale specific, and you may define rules for as many different
 # locales as you wish. All of these examples are active by default:
 # ActiveSupport::Inflector.inflections(:en) do |inflect|
-#   inflect.plural /^(ox)$/i, "\1en"
-#   inflect.singular /^(ox)en/i, "\1"
-#   inflect.irregular "person", "people"
+#   inflect.plural /^(ox)$/i, '\1en'
+#   inflect.singular /^(ox)en/i, '\1'
+#   inflect.irregular 'person', 'people'
 #   inflect.uncountable %w( fish sheep )
 # end
 
 # These inflection rules are supported but not enabled by default:
 # ActiveSupport::Inflector.inflections(:en) do |inflect|
-#   inflect.acronym "RESTful"
+#   inflect.acronym 'RESTful'
 # end

config/initializers/per_form_csrf_tokens.rb

@@ -0,0 +1,4 @@
+# Be sure to restart your server when you modify this file.
+
+# Enable per-form CSRF tokens.
+Rails.application.config.action_controller.per_form_csrf_tokens = true

config/initializers/request_forgery_protection.rb

@@ -0,0 +1,4 @@
+# Be sure to restart your server when you modify this file.
+
+# Enable origin-checking CSRF mitigation.
+Rails.application.config.action_controller.forgery_protection_origin_check = true

config/initializers/wrap_parameters.rb

@@ -5,10 +5,10 @@
 
 # Enable parameter wrapping for JSON. You can disable this by setting :format to an empty array.
 ActiveSupport.on_load(:action_controller) do
-  wrap_parameters format: [:json] if respond_to?(:wrap_parameters)
+  wrap_parameters format: [:json]
 end
 
 # To enable root element in JSON for ActiveRecord objects.
 # ActiveSupport.on_load(:active_record) do
-#  self.include_root_in_json = true
+#   self.include_root_in_json = true
 # end

config/puma.rb

@@ -1,15 +1,47 @@
-workers Integer(ENV["WEB_CONCURRENCY"] || 2)
-threads_count = Integer(ENV["MAX_THREADS"] || 5)
+# Puma can serve each request in a thread from an internal thread pool.
+# The `threads` method setting takes two numbers a minimum and maximum.
+# Any libraries that use thread pools should be configured to match
+# the maximum value specified for Puma. Default is set to 5 threads for minimum
+# and maximum, this matches the default thread size of Active Record.
+#
+threads_count = ENV.fetch("RAILS_MAX_THREADS") { 5 }.to_i
 threads threads_count, threads_count
 
-preload_app!
+# Specifies the `port` that Puma will listen on to receive requests, default is 3000.
+#
+port        ENV.fetch("PORT") { 3000 }
+
+# Specifies the `environment` that Puma will run in.
+#
+environment ENV.fetch("RAILS_ENV") { "development" }
 
-rackup DefaultRackup
-port ENV["PORT"] || 3000
-environment ENV["RACK_ENV"] || "development"
+# Specifies the number of `workers` to boot in clustered mode.
+# Workers are forked webserver processes. If using threads and workers together
+# the concurrency of the application would be max `threads` * `workers`.
+# Workers do not work on JRuby or Windows (both of which do not support
+# processes).
+#
+workers ENV.fetch("WEB_CONCURRENCY") { 2 }
 
+# Use the `preload_app!` method when specifying a `workers` number.
+# This directive tells Puma to first boot the application and load code
+# before forking the application. This takes advantage of Copy On Write
+# process behavior so workers use less memory. If you use this option
+# you need to make sure to reconnect any threads in the `on_worker_boot`
+# block.
+#
+preload_app!
+
+# The code in the `on_worker_boot` will be called if you are using
+# clustered mode by specifying a number of `workers`. After each worker
+# process is booted this block will be run, if you are using `preload_app!`
+# option you will want to use this block to reconnect to any threads
+# or connections that may have been created at application boot, Ruby
+# cannot share connections between processes.
+#
 on_worker_boot do
-  # Worker specific setup for Rails 4.1+
-  # See: https://devcenter.heroku.com/articles/deploying-rails-applications-with-the-puma-web-server#on-worker-boot
-  ActiveRecord::Base.establish_connection
+  ActiveRecord::Base.establish_connection if defined?(ActiveRecord)
 end
+
+# Allow puma to be restarted by `rails restart` command.
+plugin :tmp_restart

config/routes.rb

@@ -1,4 +1,9 @@
 Rails.application.routes.draw do
+  # For details on the DSL available within this file, see http://guides.rubyonrails.org/routing.html
+
+  # Serve websocket cable requests in-process
+  # mount ActionCable.server => '/cable'
+
   root "pages#index"
 
   get "simple", to: "pages#simple"